package string;

import java.util.Scanner;

public class ClassWork {
    public static void main(String[] args) {
        String code = generateVeriCode((int)(Math.random()*7+4));
        System.out.println("验证码为："+code);
        Scanner scan = new Scanner(System.in);
        while (true) {
            System.out.println("请输入验证码:");
            String Code = scan.next();
            if ((code.toUpperCase().equals(Code.toUpperCase()))){
                System.out.println("输入正确");
                break;
            }else {
                System.out.println("输入有误");
            }
        }
    }
    public static String generateVeriCode(int len){
        String code = "";
        char[] chs = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
                'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
                '0','1','2','3','4','5','6','7','8','9'};
        for(int i=0;i<len;i++){
            code += chs[(int) (Math.random()* chs.length)];
        }
        return code;
    }
}
